Traveling-wave tubes employ an axial high voltage electron beam with a slow-wave structure disposed therearound. The slow-wave structures are of several configurations, for example, helical, bifilar helical, and rings. Sometimes the helixes, particularly the multifilar helixes, are ring-strapped to short out opposite sides of opposite helixes. The diameter of the slow-wave structure is a function of the coupling efficiency, frequencv and power. Consequently, the critical shape of the slow-wave structure must be maintained to achieve the desirable characteristics of the traveling-wave tube.
In previous manufacturing practices, slow-wave structures have been manufactured using a complex process of mandrel winding, brazing, grinding, and deburring. However, problems have arisen with controlling the angle of the helix and in the deburring of such structures. The mandrel winding, brazing, grinding, and deburring of such parts is difficult, especially because the parts of smaller size are very delicate. In addition, manufacturing problems are increased by the fact that the materials are refractory. Molybdenum and tungsten are preferred metals for such slow-wave structures and are by nature brittle and difficult to form. Accordingly, there is need for a manufacturing process which economically and accurately provides parts which by prior methods were difficult to manufacture.